An agitation/deaeration apparatus in which a container containing a to-be-kneaded object is revolved, and rotated in a revolution orbit, has been hitherto known in the art.
This type of the agitation/deaeration apparatus is configured to press a to-be-kneaded object against an interior wall of the container centrifugally by the action of revolution of the container, thus releasing bubbles incorporated in the to-be-kneaded object to the outside (deaerating), and to agitate the to-be-kneaded object by the action of rotation of the container, at the same time. For the purpose of achieving desired effects, such as promotion of deaeration and agitation of the to-be-kneaded object, an external device may be connected with the container to be rotated, through wiring or piping, in some instances.
FIG. 6 illustrates such an instance where an external device is connected with a container 109 of an agitation/deaeration apparatus 101; particularly, the external device connected therewith is a pressure-reducing means 120 for reducing a pressure in the container. Herein, the container 109 is gastight so that a to-be-kneaded object K included in a sample holder 109d is sealed therein. At the center of a top lid 109b thereof is provided a fixed attachment part 109e having an opening to which an end of a suction tube 108 made of a hollow flexible hose is fixed. At the center of an undersurface of a container body 109a, a rotation shaft of a rotating means (not shown) is provided and connected thereto so that the container 109 is rotated about a rotation axis Y2. Further, this rotating means is placed in a revolving means (not shown) so that the container 109 revolves about a revolution axis Y1 in a revolution orbit X.
A vacuum pump 122 and the container 109 are connected together through a rotary joint 108a by which the suction tube 108 and a vacuum suction hose 121 are rotatable relative to each other (for example, see JP11-290668 A, paragraphs 0030-0035, FIG. 3). The rotary joint 108a is comprised of pipes joined together so that the pipes are coaxially rotatable relative to each other while its joint portion is adapted to prevent outside aeriform fluids from entering inside therethrough under atmospheric pressure even when the inside of the pipes is under reduced pressure.
As described above, previously, joint of an external device (pressure-reducing means in this instance) with the container 109 to be rotated is achieved by providing a rotary joint 108a or any other member which permits pipes coupled with its ends to rotate relative to each other, at some midpoint in the suction tube 108.
However, the use of a standard rotary joint 108a provided at a midpoint in such a coupling member would disadvantageously suffer from a limitation of vacuum level (to an extent of a few torr or so) achieved by reduction in pressure inside the container 109 in which the to-be-kneaded object K is included. This is because leakage of atmospheric gases into the suction tube 108 cannot completely be prevented even if sealing for ensuring gastightness is provided at a portion where the rotary joint 108a slides to rotate. The use of an alternative rotary joint having a special structure such as those which adopt a scheme using a magnetic fluid could carry out agitation/deaeration in a higher degree of vacuum, but would hardly be applicable in view of its cost and size.
Assuming an application to a technical field in which a sensor or the like is provided in the container 109 to be rotated for determining physical properties of the to-be-kneaded object K during a kneading operation, which are observed with an external device, a feeble analog signal sensed by the sensor could be passed through a sliding contact inside the rotary joint 108a, and transmitted to the external device. Noises that could be produced at the sliding contact, however, would be transmitted too, with the result that a signal-to-noise ratio of the detected signal would disadvantageously decrease.
Therefore, it is an object of the present invention to solve the aforementioned problems, and to provide an agitation/deaeration apparatus which is configured to rotate a container without causing tubes (wires) for connecting the container and an external device to become twisted.